Method of removing a bearing seal assembly

ABSTRACT

A bearing seal assembly includes a seal case having large and small diameter circumferential walls, a radial connecting wall interconnecting the circumferential walls, and a radial end wall at the outermost end of the small circumferential wall. The free end of the large circumferential wall is press fitted into a socket at the end of a bearing cup so that the small diameter wall projects away from the bearing cup and the bearing cone encircled by that cup. The seal assembly further includes an elastomeric seal having a supporting portion which is bonded to the inner surfaces of the small circumferential wall and the radial end wall. The supporting portion is joined to a seal lip through a web, and that lip engages a wear surface as the cone and cup of the bearing rotate relative to one another. The supporting portion is provided with a shoulder which faces the interior of the bearing and provides a seat against which a removal tool bears for detaching the seal assembly from the bearing cup. The supporting portion is bonded to the seal case for substantial distances on each side of the shoulder so that the removal force does not separate the seal case and the seal.

United States Otto atent H 1 [451 May 1, 1973 METHOD OF REMOVING ABEARING SEAL ASSEMBLY Dennis L. Otto, Malvem, Ohio [73] Assignee: TheTimken Company, Canton,

Ohio

[22] Filed: Apr. 19, 1971 [2l] Appl.No.: 135,168

[75] Inventor:

Primary ExaminerThomas H. Eager AttorneyGravely, Lieder & Woodruff [5 7]ABSTRACT A bearing seal assembly includes a seal case having large andsmall diameter circumferential walls, a radial connecting wallinterconnecting the circumferential walls, and a radial end wall at theoutermost end of the small circumferential wall. The free end of thelarge circumferential wall is press fitted into a socket at the end of abearing cup so that the small diameter wall projects away from thebearing cup and the bearing cone encircled by that cup. The sealassembly further includes an elastomeric seal having a supportingportion which is bonded to the inner surfaces of the smallcircumferential wall and the radial end wall. The supporting portion isjoined to a seal lip through a web, and that lip engages a wear surfaceas the cone and cup of the bearing rotate relative to one another. Thesupporting portion is provided with a shoulder which faces the interiorof the bearing and provides a seat against which a removal tool bearsfor detaching the seal assembly from the bearing cup. The supportingportion is bonded to the seal case for substantial distances on eachside of the shoulder so that the removal force does not separate theseal case and the seal.

1 Claim, 4 Drawing Figures METHOD OF REMOVING A BEARING SEAL ASSEMBLYBACKGROUND OF THE INVENTION This invention relates in general to sealassemblies and more particularly to a method of detaching a sealassembly from a bearing assembly without damaging the seal assembly.

All-purpose tapered roller bearings are normally provided with sea]assemblies for retaining lubricants within the vicinity of the bearingrollers and raceways. These seal assemblies usually consist of a sealcase and an elastomeric seal which is attached to the case and embracesa shaft or wear ring which rotates relative to the case and the bearingcup. In the typical seal construction, the seal case possesses twocircuiferential steps of different diameter. The larger step is pressfitted into the bearing cup, while the elastomeric seal is containedwholly within the smaller step. The typical seal also includes aso-called spring retainer or inner case contained within the smallerstep and having a separating wall located immediately inwardly from theelastomeric seal. The separating wall provides a surface for locatingthe removal tool which is used to detach the seal case from the bearingcup. In particular, the removal tool is inserted through the bearing andlocated against the separating wall, at which time an outwardly directedaxial force is applied to that wall. This force, of course, istransferred to the seal case and overcomes the interference fit betweenthe large diameter step and the bearing cup, thus freeing the seal casefrom the cup. Occasionally, the axial force will deform the separatingwall of the inner case before the outer step breaks away from thebearing cup, and when this occurs the nearby elastomeric seal is usuallydistorted to the extent that it will not properly seat against the wearring or shaft when the seal case is again installed in the bearing cup.This in turn results in a defective seal.

SUMMARY OF THE INVENTION One of the principal objects of the presentinvention is to provide a process for removing a seal assembly from abearing cup without damaging or permanently distorting the seal lip.Another object is to provide a process for removing a seal assemblyhaving the elastomeric seal bonded to a relatively large area of theseal case. An additional object is to provide a process for removing aseal assembly which dispenses with the inner seal case found in typicalseals and therefore does not contain a metal member which willpermanently deform when subjected to removal forces. These and otherobjects and advantages will become apparent hereinafter.

The present invention is embodied in a process for removing a bearingseal assembly having a seal case and an elastomeric seal bonded to theseal case. The seal has a shoulder against which an axial force isapplied for removing the seal assembly from a bearing.

I The invention also consists in the parts and in the arrangements andcombinations of parts hereinafter described and claimed.

DESCRIPTION OF THE DRAWINGS In the accompanying drawings which form partof the specification and wherein like numerals refer to like partswherever they occur:

FIG. 1 is a fragmentary sectional view of a bearing assembly providedwith the seal assemblies constructed in accordance with the embodyingthe present invention;

FIG. 2 is an enlarged sectional view of the seal assembly illustrated inFIG. 1;

FIG. 3 is a sectional view showing the seal assembly being removed fromhe bearing; and

FIG. 4 is a sectional view of a modified seal assembly.

DETAILED DESCRIPTION Referring now in detail to the drawings, 2designates a bearing assembly (FIG. I) positioned between an axle or ashaft 4 and a containing structure 6 such as an adapter or bearinghousing in the side frame of a rail car truck. The bearing assembly 2,of course, permits the shaft 4 to rotate freely relative to thecontaining structure 6. The shaft 4 is provided with a reduced end 8which merges into the remainder of the shaft 4 at a shoulder 10, and itis the reduced end 8 which projects into the bearing assembly 2 andcontaining structure 6.

The bearing assembly 2 from its outer end inwardly includes (FIG. 1) anend cap 12 positioned across the end face of the reduced shaft end 8, anoutboard wear ring 14, a tapered roller bearing 16, an inboard wear ring18, and a backing ring 20. The end cap 12 is secured to the shaft 4 bybolts 21 qhich thread into the reduced shaft end 8, and whn tightenedcompress the outboard wear ring 14, the bearing 16, the inboard wearring 18 and the backing ring 20 between the end cap 12 and the shaftshoulder 10.

The bearing 16 includes (FIG. 1) a pair of cones 22 and 24 through whichthe shaft end 8 extends, and these cones 22 and 24 have outwardlypresented raceways and are separated by a spacer 26. Thecone 22, thespacer 26, and the cone 24 are clamped firmly together in that orderbetween the outboard wear ring 14 and the inboard wear ring 18, which inturn are clamped between the end cap 12 and the backing ring 20, so thatthe bearing 16 does not shift axially on the shaft 4. In addition to thecones 22 and 24 and the spacer 26, the bearing 16 also includes a doublecup 28 which fits into the containing structure 6 and has a pair ofinwardly presented raceways located opposite to the raceways of the twocones 22 and 24. The bearing 16 further includes tapered rollers 30which are fitted between the cup 28 and the cones 22 and 24 and areengaged with the opposed raceways thereon. The rollers 30, accordingly,are arranged in two rows, and the individual rollers 30 of each row areseparated by a cage 32. Beyond the large diameter ends of its raceways,the cup 28 is provided with short outwardly opening sockets 34 whichpossess a cylindrical configuration. At their outer ends the sockets 34are provided with charnfers 36, and at their inner ends they arerelieved in the formation of inwardly opening grooves 38. The grooves 38separate the surfaces of the sockets 34 from the raceways of the cup 28.

Fitted into the sockets 34 at the ends of the double cup 28 and fixedfirmly with respect to the cup 28 are seal assemblies 40 and 42 (FIG. 1)which project outwardly from the cup 28 and embrace the wear rings 14and 18, respectively, for preventing lubricants from escaping from theinterior of the bearing 16. Aside from the seal assemblies 40 and 42,the foregoing bearing assembly 2 is conventional and therefore will notbe described in further detail.

The seal assemblies 40 and 42 are identical in construction, and byreason of this fact, only the seal assembly 40 will be described indetail. The seal assembly 40 includes (FIG. 2) a seal case 44 which ispreferably stamped from sheet steel and possesses a steppedconfiguration. The seal case 44 closes the end of the bearing 16 andincludes a large diameter circumferential wall 46 which fits into thesocket 34 on the outboard end of the cup 28. The diameter of the wall 46is slightly greater than the diameter of the socket 34 so that aninterference fit exists when the former is inserted into the latter. Atits one end the wall 46 is provided with an integral locking bead 48which projects outwardly therefrom and fits into the groove 38 at theinner end of the socket 34. Thus, the outer diameter of the locking bead48 is greater than the diameter of the socket 34. At its opposite endthe large circumferential wall 46 merges into a radial connecting wall50 which extends radially inwardly beyond the large diameter end facesof the tapered rollers 30, and the radial connecting wall 50 in turnmerges at its small diameter end into a small diameter circumferentialwall 52 which projects axially away from the bearing 16 and encirclesthe outboard wear ring 14, being spaced outwardly therefrom. At itsouter end the small circumferential wall 52 merges into a radial endwall 54 having an oblique lip 56 which turns axially inwardly and isdisposed between the small circumferential wall 52 and the wear ring 14.The innermost end of the lip 56 is also spaced outwardly from the wearring 14.

In addition to the seal case 44, the seal assembly 40 also includes anelastomeric seal 60 (FIG. 2) which is molded from a suitable elastomeras a unitary structure and is attached to the small circumferential wall52 and the radial end wall 54. In particular, the seal 60 includes asupporting portion 62 which is bonded to the entire inwardly presentedfaces of the small circumferential wall 52 and the radial end wall 54,including the lip 56 of the latter. The supporting portion 62 is quitenarrow along that part of the circumferential wall 52 which is adjacentto radial connecting wall 50, and indeed, the innermost end of thisnarrow segment curves around the inside comer formed by the juncture ofthe circumferential wall 52 and the connecting wall 50. Intermediate theends of the small circumferential wall 52 the supporting portionabruptly widens at a shoulder 64 so that between the shoulder 64 and theradial end wall 54 the wupporting portion 62 possesses substantialthickness. The face of the shoulder 64 is presented inwardly toward thebearing 16 and is perpendicular to the axis of rotation for the bearing16.

Adjacent to the radial end wall 54 the supporting portion 62 turnsinwardly and extends along the inwardly presented face of the obliquelip 56, to which it is also bonded. Near the inner end of the lip 56,the supporting portion 62 merges into an integrally formed connectingweb 66 which extends generally axially between the thick segment of thesupporting portion 62 and the outboard wear ring 14. indeed, theconnecting web 66 and the thick segment of the supporting portion 62 areseparated by an annular relief 68 in the seal 60, and the presence ofthe relief 68 allows the web 66 to flex outwardly toward the encirclingthick segment of the supporting portion 62.

At its inner end the connecting web 66 is formed integral with andsupports an oil or primary seal lip 70 formed by converging surfaceswhich intersect at a sealing edge 74 disposed radially inwardly from theconnecting web 66. The sealing edge 74 engages the outwardly presentedsurface of the outboard wear ring 14, and this engagement creates abarrier which appreciably retards the leakage of grease and oil alongthe wear ring 14. On its back side, the seal lip 70 has a retaininggroove 76 of semi-circular cross-sectional shape, and this groove 76opens into the annular relief 68. Fitted into the groove 76 and retainedby the walls thereof is a garter spring 78 which extendscircumferentially around the seal lip 70 and urges its sealing edge 74into snug engagement with the wear ring 14. Finally, it should be notedthat the entire seal lip 70 is axially offset from the shoulder 64, andthe axial offset is such that the seal lip 70 is disposed axiallyoutwardly from the shoulder 64.

The opposite or outer end of the connecting web 66 merges into asecondary or dust lip 80 which is disposed radially inwardly from theoblique lip 56 and is considerably smaller than the primary lip 70. Likethe primary lip '70, the dust lip 80 has converging surfaces whichintersect at a sealing edge 84. That edge 84 also engages the wear ring14 axially outwardly from the edge 74 of the primary lip 70, and itsprimary purpose is to prevent the entry of dust, grit and othercontaminants into the interior of the bearing 16.

When the shaft 4 rotates relative to the containing structure 6, thecones 22 and 24 will rotate relative to the double cup 28 and therollers 30 will roll along the opposed raceways of the cones 22 and 24and the cup 28. The wear rings 14 and 18, being clamped against thecones 22 and 24, will likewise rotate with the shaft 4, whereas the sealassemblies 40 and 42 remain fixed to the cup 28. Accordingly, the wearrings 14 and 18 rotate relative to the seal assemblies 40 and 42. Theseal assemblies 40 and 42 close the ends of the bearing 16, and as theshaft 4 rotates relative to the containing structure 6 the seal lips 70and 80 at their sealing edges 74 and 84, respectively, engage and wipethe outwardly presented surfaces of the wear rings 14 and 18. The seallips 70 prevent the lubricant contained within the bearing 16 fromescaping, whereas the lips 80 prevent the entry of dirt, grit and othercontaminants into the bearing 16.

The seal case 44 of each seal assembly 40 and 42 is, of course, formedseparate from the bearing 16. To install each of the seal assemblies 40and 42 in the double cup 28, the free end of the large circumferentialwall 46 slides across the surface of the socket 34, and once the largediameter circumferential wall 46 is fully inserted into the socket 34,the bead 48 will snap outwardly into the inwardly opening groove 38 atthe end of the tapered cup raceway. This enables the adjoining portionof the circumferential wall 46 to expand and snugly engage the surfaceof the socket 34. The disposition of the locking bead 48 in the groove38 axially positions and retains the seal case 44 in its cup socket 34,while the interference fit between the circumferential wall 46 and thesurface of the socket 34 prevents the seal case 44 from rotatingrelative to the cup 28.

In order to disassemble the bearing 16 it is necessary to remove it fromthe shaft 4 and containing structure 6. The bearing 16 is easilydetached from the shaft 4 by withdrawing the bolts 21 and removing theend cap 12 from the reduced end 8. Once the end cap 12 is removed, thereduced shaft end 8 is withdrawn from the cones 22 and 24 and spacer 26of the bearing 16 as well as from the wear rings 14 and 18 and backingring 20. While the bearing 16 is then free of the shaft 4, it is stillheld together by the seal assemblies 40 and 42 at each of its ends. Inother words, the seal assemblies 40 and 42 prevent the cones 22 and 24from being withdrawn from the double cup 28.

After the bearing 16 is free of shaft 4 and the wear rings 14 and 16have been removed from the seal assemblies 40 and 42, one end of thedouble cup 28 is inserted in a bearing support ring 90 (FIG. 3) havingthree bores 92, 94, and 96 which are progressively larger in size. Thesmallest bore 92 is sized to loosely receive the small diametercircumferential wall 52; the intermediate bore 94 is sized to looselyreceive large circumferential wall 46; while the largest bore 96 isrelatively short and loosely receives one end of the cup 28. Indeed, thebores 94 and 96 are separated by a shoulder 98 and the end of the cup 28rests upon this shoulder 98.

Once the cup 28 is fitted into the support ring 90, a removal tool 100(FIG. 3) is inserted through the bearing 16 until its lead end is in thevicinity of the seal assembly 40, that is the seal assembly which isdisposed partially within the support ring 90. The removal tool 100 hasa shank 102 which is somewhat longer than the bearing 16 and at its leadend is provided with a head 104 or nut to which retractable or removablejaws 106 are attached. The jaws 106 when retracted or removed allow thetool 100 to pass through the two cones 22 and 24 and the spacer 26.However, when extended or inserted the jaws 106 project outwardly to thethin segment of the supporting portion 62 forming part of theelastomeric seal 60. Indeed, the jaws 106 may be held in the retractedor removed position until they align with the space between the shoulder64 for the seal 40 and the end face of the adjacent cone 22. Once theyalign with this space, the jaws 106 may be extended or inserted untiltheir outer surfaces are located adjacent to the thin segment of thesupporting portion 62 for the seal ring 60 and their forward faces arepositioned opposite to the shoulder 64. If removable jaws are used nut104 is installed at this time, holding jaws 106 in position.

Thereupon an axial force is app'ied to the shank 102, and this force istransmitted to the seal assembly 40 at the shoulder 64 thereon. Morespecifically, upon the application of the axial force the jaws 106 bearagainst the radial surface of the shoulder 64, and this force istransmitted to the seal case 44 along the extended bond between thesupporting portion 62, on one hand, and the small diametercircumferential wall 52 and radial end wall 54, on the other.

The axial force overcomes the interference fit between the socket 34 andthe large circumferential wall 46 and further brings the locking bead 48against the side of the groove 38, causing that bead 48 to be cammedinwardly. This contracts the end of the large diameter circumferentialwall 46 and allows the bead 48 to pass along the surface of the socket34. Once the bead 48 reaches the end of the socket 34, the entire sealassembly 40 falls free of the cup 28 and drops into the bores 92 and 94of the support ring 90.

While the thick segment of the elastomeric supporting portion 62 istemporarily deformed to a limited extent at the shoulder 64 upon theapplication of force to that shoulder, the deformation is not enough toenable the jaws 106 of the removal tool 100 to damage the axiallyofi'set seal lip 70. In other words, the lip is offset sufficiently fromthe shoulder 64 to prevent damage thereto by the jaws 106 of the tool100. Moreover, the supporting portion 62 retains the full thickness ofits shoulder 64 beyond the shoulder 64, so that the removal force is notonly transmitted through the bond between the supporting portion 62 andthe small circumferential wall 52, but is also transmitted through thethick segment of the supporting portion 62 to the radial end wall 54.Thus, the elastomeric seal 60 remains firmly bonded to the seal case 44,notwithstanding the application of substantial removal force to the seal60 at the shoulder 64 thereon.

The seal assemblies 40 and 42 contain a minimal number of components andcan therefore be easily manufactured.

It is possible to provide a modified seal assembly 1 10 (FIG. 4) whichis very similar to the seal assembly 40. However, the supporting portion62of the elastomeric seal 60 for the seal assembly 110, is not bonded tothe entire inwardly presented surface of the small circumferential wall52 and radial end wall 54, but is instead bonded partially to thosewalls 52 and 54 and also to a steel reinforcing ring 112 which is fittedinto the small circumferential wall 52 and against the end wall 54. Theseal 60 is molded completely around the reinforcing ring 112 so thatthereinforcing ring 112 is in effect captured between the molded supportingportion 62, on one hand, and the small circumferential wall 52 andradial end wall 54, on the other hand. i

The reinforcing ring 1 12 extends axially inwardly beyond the seal lip70 and provides a rigid backing for the shoulder 64. Consequently, whenthe removal force is applied to that shoulder 64, defonnation of thesupporting section 62 is minimal.

This invention is intended to cover all changes and modifications of theexample of the invention herein chosen for purposes of the disclosurewhich do not constitute departures from the spirit and scope of theinvention.

What is claimed is:

l. A process for removing a seal assembly from a bearing, the sealassembly including a seal case having bearing; said process comprising:inserting a jaw-type removal tool into the bearing; positioning the jawsof the tool so that they are presented to engage the shoulder on theelastomeric supporting portion of the seal; and applying an axiallydirected force to the tool, whereby the force is transmitted to the sealassembly at the shoulder on the supporting portion.

* t It ill

1. A process for removing a seal assembly from a bearing, the sealassembly including a seal case having a first circumferential wallfrictionally engaged with a component of the bearing and a secondcircumferential wall located axially outwardly from the firstcircumferential wall and projecting away from the bearing, the sealassembly also including an elastomeric seal having a supporting portionwhich is bonded to the second circumferential wall and a seal lipconnected to the supporting portion, the supporting portion having ashoulder formed thereon and facing the interior of the bearing; saidprocess comprising: inserting a jaw-type removal tool into the bearing;positioning the jaws of the tool so that they are presented to engagethe shoulder on the elastomeric supporting portion of the seal; andapplying an axially directed force to the tool, whereby the force istransmitted to the seal assembly at the shoulder on the supportingportion.